FIG. 1 illustrates a conventional base station arrangement for a plurality of antenna sites 10. A base station 20 is provided at each antenna site 10. Each base station 20 comprises radio equipment 25 and a radio equipment controller 26. Typically, the radio equipment controllers 26 perform baseband signal generation and/or processing and the radio equipment 25 perform analogue and radio frequency functions such as filtering, modulation, frequency conversion and amplification.
A problem with this arrangement however is that it is difficult to establish X2 connections between adjacent base stations 20. X2 connections are logical or even physical connections which enable power and traffic information to be correlated between adjacent base stations 20, reducing interference and increasing data throughput (bit spectral efficiency).
More recently, a centralised base station system as illustrated in FIG. 2 has become popular. Instead of locating both the radio equipment 25 and the radio equipment controllers 26 at the respective antenna sites 10, only the radio equipment 25 is located at the antenna sites 10. The radio equipment controllers 26 are located remote from the antenna sites 10 at a common site, which is sometimes referred to as a base station hub or baseband hotel 30. The base station hub 30 is connected to each of the radio equipment 25 by a transport infrastructure 40 which may support the communication of, for example, common public radio interface (CPRI) signals between the radio equipment controller 26/radio equipment 25 pairs. The base station hub 30 further has a network interface (not shown) for communication with a core network to transmit and receive mobile traffic.
This arrangement has the advantage that the exchange of information between base stations 20 (X2 connections) is more straightforward. Furthermore, the base station hub 30 may be located in a convenient, low cost location, for example in the basement of a building or an out of town industrial site, which may make it easier to secure the radio equipment controllers 26 and to access the radio equipment controllers 26 to perform maintenance.